Thin Flexible Toothbrush Head With Monolithic Bristle Unit

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Solution Overview

Problem

Conventional toothbrushes with nylon bristles are inflexible and bulky, making it difficult to clean hard-to-reach areas in the oral cavity, such as the back of the mouth.

Innovation Solution

An oral care implement with a head comprising a support structure and a monolithic cleaning unit, where the head has a reduced thickness of less than 3.5mm, featuring a through-hole that extends at least 50% of its width, allowing increased flexibility and deeper reach into the oral cavity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional toothbrushes use nylon bristles with a thick head structure, then the bristles can be securely attached to the toothbrush head, but the head becomes inflexible and bulky, making it difficult to reach deep into the oral cavity

Engineering Contradiction:
Improvebristle attachment strengthVSAvoidhead flexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent changes the material parameter from conventional nylon bristles to elastomeric material, and changes the head thickness parameter from conventional thick structure to less than 3.5mm. This allows the bristles to be securely attached while maintaining head flexibility for reaching deep into the oral cavity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a thin head structure with thickness less than 3.5mm, which acts as a flexible element allowing the toothbrush head to bend and reach deep into the oral cavity while maintaining sufficient strength through the elastomeric material properties.

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If the toothbrush head thickness is reduced to increase flexibility, then the head can reach deeper into the oral cavity, but the structural integrity and bristle securing capability may be compromised

Engineering Contradiction:
Improvehead flexibilityVSAvoidhead structural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent uses composite construction with a support plate and an elastomeric cleaning unit with molded bristles. This composite structure provides both the flexibility needed for deep reach and the structural integrity to secure bristles effectively, overcoming the limitation of simple thin-head designs.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent incorporates a transverse cross-section design with curved surfaces and optimized geometry in the support plate and cleaning unit, which distributes structural loads effectively while maintaining thin overall thickness, thereby preserving both flexibility and strength.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of operation

If elastomeric material is used to form bristles, then the head flexibility increases, but the manufacturing complexity and material selection requirements increase

Engineering Contradiction:
Improvehead flexibilityVSAvoidmaterial composition complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the support plate and cleaning unit into an integrally molded structure where elastomeric material forms both the bristles and the cleaning unit body in one piece. This reduces manufacturing complexity compared to assembling separate components, while maintaining the flexibility benefits of elastomeric material.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the head thickness is reduced to less than 3.5mm, then the flexibility and reach into oral cavity improve, but the available space for bristle arrangement and support structure may be reduced

Engineering Contradiction:
Improveoral cavity reachVSAvoidhead internal space
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent applies local quality by concentrating the bristle arrangement and support structure in specific regions of the cleaning unit, optimizing the use of limited internal space within the thin head structure to maintain effective brushing capability while preserving overall flexibility.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3664661B1Oral care implement
Publication Date: 2026.04.01 COLGATE PALMOLIVE CO
  • EP3664661B1 patent drawingFigure 1
  • EP3664661B1 patent drawingFigure 2A
  • EP3664661B1 patent drawingFigure 2B

AI summary

An oral care implement that includes a handle and a head. The head, which has an exposed front surface and an exposed rear surface, may include a support structure having a perimetric wall that defines a central opening and a monolithic cleaning unit including a pad located within the central opening and molded bristles extending from the pad. The support structure and the pad may collectively define the exposed front surface and the exposed rear surface of the head. Furthermore, the support structure may have a maximum thickness of 3mm or less measured from a front surface of the perimetric wall to a rear surface of the perimetric wall.